From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Douglas RAILLARD <douglas.raillard@arm.com>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
viresh.kumar@linaro.org, mingo@redhat.com
Subject: Re: [PATCH] sched/cpufreq: Align trace event behavior of fast switching
Date: Wed, 28 Aug 2019 11:44:30 +0200 [thread overview]
Message-ID: <58065333.3TlMmDsHGl@kreacher> (raw)
In-Reply-To: <20190826094058.GP2369@hirez.programming.kicks-ass.net>
On Monday, August 26, 2019 11:40:58 AM CEST Peter Zijlstra wrote:
> On Mon, Aug 26, 2019 at 11:10:52AM +0200, Rafael J. Wysocki wrote:
> > On Wednesday, August 7, 2019 5:33:40 PM CEST Douglas RAILLARD wrote:
> > > Fast switching path only emits an event for the CPU of interest, whereas the
> > > regular path emits an event for all the CPUs that had their frequency changed,
> > > i.e. all the CPUs sharing the same policy.
> > >
> > > With the current behavior, looking at cpu_frequency event for a given CPU that
> > > is using the fast switching path will not give the correct frequency signal.
> > >
> > > Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
> > > ---
> > > kernel/sched/cpufreq_schedutil.c | 7 ++++++-
> > > 1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> > > index 1f82ab108bab..975ccc3de807 100644
> > > --- a/kernel/sched/cpufreq_schedutil.c
> > > +++ b/kernel/sched/cpufreq_schedutil.c
> > > @@ -153,6 +153,7 @@ static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
> > > unsigned int next_freq)
> > > {
> > > struct cpufreq_policy *policy = sg_policy->policy;
> > > + int cpu;
> > >
> > > if (!sugov_update_next_freq(sg_policy, time, next_freq))
> > > return;
> > > @@ -162,7 +163,11 @@ static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
> > > return;
> > >
> > > policy->cur = next_freq;
> > > - trace_cpu_frequency(next_freq, smp_processor_id());
> > > +
> > > + if (trace_cpu_frequency_enabled()) {
> > > + for_each_cpu(cpu, policy->cpus)
> > > + trace_cpu_frequency(next_freq, cpu);
> > > + }
> > > }
> > >
> > > static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time,
> > >
> >
> > Peter, any comments here?
>
> I was thinking this would be a static map and dealing with it would be
> something trivially done in post (or manually while reading), but sure,
> whatever:
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
Thanks, queuing up this one for 5.4.
prev parent reply other threads:[~2019-08-28 9:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 15:33 [PATCH] sched/cpufreq: Align trace event behavior of fast switching Douglas RAILLARD
2019-08-07 20:40 ` Rafael J. Wysocki
2019-08-08 16:18 ` Douglas Raillard
2019-08-26 9:10 ` Rafael J. Wysocki
2019-08-26 9:40 ` Peter Zijlstra
2019-08-26 9:51 ` Dietmar Eggemann
2019-08-26 11:24 ` Peter Zijlstra
2019-08-26 12:12 ` Dietmar Eggemann
2019-08-28 9:44 ` Rafael J. Wysocki [this message]
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